Visible–near-Infrared Light-Driven Photocatalytic Characteristics of Er<sup>3+</sup>/Yb<sup>3+</sup>-Codoped BiOBr Upconverting Microparticles for Tetracycline Degradation
Peng Du, Laihui Luo, Di Wang, Weiping Li, Dandan Wang, Zhihong Mai, Ye Wang, Weiguang Ran, Guozhong Xing
Abstract
To settle the unsatisfying efficiency and insufficient light harvesting ability of photocatalysts, we report on the development of Er3+/Yb3+-codoped BiOBr (BiOBr:Er3+/xYb3+) microparticles that were synthesized by a rational high-temperature solid-state reaction method. The prepared microcrystals exhibit high visible upconversion (UC) emissions with maximum intensities at x = 0.01 when excited by a 980 nm laser. Remarkably, the corresponding UC emission process is attributed to a two-photon absorption route. Furthermore, the photocatalytic activities of as-synthesized compounds were further evaluated through analyzing the visible–near-infrared light-triggered tetracycline degradation. Compared with BiOBr:Er3+ microparticles, BiOBr:Er3+/xYb3+ microparticles present superior photocatalytic properties and the optimal status is achieved when x = 0.05, in which h+, ·O2–, and ·OH active species contribute to the photocatalytic mechanism. Additionally, the designed microparticles exhibit better photocatalytic abilities than previously reported photocatalysts (i.e., TiO2, SnO2) upon full-spectrum light irradiation. These results reveal that Yb3+ codoping is able to not only enhance the UC emission properties of BiOBr:Er3+ microparticles but also reinforce their photocatalytic activities. Our findings may put forward a facile strategy to regulate the photodegradation capacity of photcatalysts.